1. Field
Example embodiments relate to a method of channel pre-charge and program operation of a nonvolatile memory device, and, more particularly, to a method of two-step channel pre-charge and program operation of a nonvolatile memory device.
2. Description of Related Art
Semiconductor memory devices are generally the most inevitable micro electronic parts for digital logic devices, e.g., a computer and a microprocessor used in applications ranging from a satellite to a consumer electronic product. Therefore, improving manufacturing technology of semiconductor memory devices, including process and technique development acquired through scale-down for high integration and high speed, has helped to improve performance criteria of other digital logic devices.
Semiconductor memory devices are largely divided into volatile semiconductor memory devices and nonvolatile semiconductor memory devices. In volatile memory devices, information is stored by setting logic state of bi-stable flip-flop in case of SRAM and by charging a capacitor in case of DRAM. Also, volatile memory devices can store and read data only while power is supplied, i.e., lose data when power is removed. In contrast, nonvolatile memory devices, e.g., MROM, PROM, EPROM, EEPROM, etc. can store data even when power is removed. Data state in nonvolatile memory devices may be stored permanently or may be reprogrammed according to manufacturing process. Reprogrammable nonvolatile semiconductor memory devices have been used to store data and program code in wide range of applications, e.g., computer, avionics, telecommunication, and consumer electronic technique industry.
In nonvolatile memory devices including flash memory devices, bit line pre-charge operation is often required to avoid a program disturbance phenomenon. The bit line pre-charge operation uses a power supply voltage to pre-charge bit lines according to data to be programmed. However, as the memory devices are designed to consume less power, i.e., the power supply voltage is decreased, inadequate pre-charging may occur, resulting in a program disturbance phenomenon.